Use OrderContents#update_cart in Api::PaymentsController#create

[jordan-brough]

First step in getting all payment creation code going through a common
path.

@jhawthorn @cbrunsdon @gmacdougall @athal7 @magnusvk here's a first step in the direction we talked about this afternoon. I haven't started making a CartUpdate class or anything yet but I'm trying to tackle this incrementally and I think this change can stand on its own, but definitely open to any thoughts.

[athal7]

would this respond with the correct payment in a failed scenario? it wouldn't be the order's last payment would it?

[jordan-brough]

Yeah I was worried about that also but it's cached inside the association since we just tried to add it through the association. There's a spec that verifies this:

solidus/api/spec/controllers/spree/api/payments_controller_spec.rb

Line 54 in 458efae

expect(json_response['errors']['source']).to eq(["can't be blank"])

[athal7]

ah cool. if it were me i'd probably want a separate add_payment method that update_cart would use if it detects nested params as opposed to the other way around. but i think this is fine as well. 👍

[jordan-brough]

@athal7 cool, yeah, just trying to stay real minimal for the moment before moving on to better stuff like that.

[magnusvk]

👍 @jhawthorn does this look good to you?

[jordan-brough]

ping @jhawthorn

[jordan-brough]

@jhawthorn if you're going to start working on the "CartUpdate" idea perhaps we should have this use CartUpdate instead of update_cart?

[jordan-brough]

This is taken care of in #357